Mid$
sResult = Mid$ ( sSource AS String , iStart AS Integer [ , iLength AS Integer ] ) AS String
sResult = Mid ( sSource AS String , iStart AS Integer [ , iLength AS Integer ] ) AS String
Returns a
String, which is that part of the source
String sSource, which starts as position
iStart
and has the length
iLength.
If
iLength is not specified, everything from the position
iStart to the end is returned.
If
iLength is negative, everything from the position
Start except the (-
iLength ) last characters is returned.
Mid$ is optimized so that no string duplication occurs to generate the result.
This function only deals with ASCII strings. To manipulate UTF-8 strings, use the String.
Mid class.
Using string like arrays (as known as "Boxed strings")
Since 3.12
You can get the contents of a string using the following array-like syntax:
Result = String [ Start As Integer [ , Length As Integer ] ]
In that case, the character positions start at index zero, not one!
Examples
PRINT Mid$("Gambas", 3, 2)
PRINT Mid$("Gambas", 4)
PRINT Mid$("Gambas", 2, -1)
Dim sStr As String = "Gambas"
Print sStr[0];;sStr[3, 2];; sStr[2, 2];; sStr[2, -1]
Mid$ (assignment)
Mid$ ( Variable AS String , Start AS Integer [ , Length AS Integer ] ) = Expression
Mid ( Variable AS String , Start AS Integer [ , Length AS Integer ] ) = Expression
This syntax allows to modify the contents of a string variable.
It is just syntactic sugar, i.e. the compiler internally replaces:
Mid$(Variable, Start, Length) = Expression
By the following code:
Variable = Left$(Variable, Start - 1) & Expression & Mid$(Variable, Start + Length)
If the third argument is not specified, i.e. if you use:
Mid$(Variable, Start) = Expression
Then the generated code will be equivalent to:
Variable = Left$(Variable, Start - 1) & Expression
In other words, everything from
Start to the end of the string is replaced!
See also